Multiple network topologies may be integrated into a cellular network to support interworking of different types of applications in one network. For example, heterogeneous networks such as macros, micros, picos, femtos and relay networks may be supported along with long-term evolution (LTE) or LTE-advance (LTE-A) network on the same frequency spectrum.
Because multiple network systems may share the same frequency spectrum, some network system may be primary systems and some secondary systems. While a primary system user or device may use all or part of allocated frequency spectrum resources to meet its application needs, a secondary system user or device may engage in opportunistic usage of radio spectrum resources of the primary system. A secondary system user may utilize spectrum of the primary system opportunistically provided that the secondary system user does not degrade performance of or interfere with the primary user. For example, while a LTE user equipment may be a primary user, a secondary user may be a machine device with wireless communication capabilities.